In order to hasten the warming up of a combustion engine from a cold start, a known practice in the case of diesel engines in heavy vehicles is to increase the pressure in the exhaust system by blocking the exhaust line by means of an exhaust brake damper usually incorporated in the exhaust line of such vehicles.
The resulting increase in the load on the engine makes it reach its normal working temperature more quickly, thereby also reducing the discharge of emissions and of so-called white smoke.
Another known practice is to incorporate a line which connects the inlet and outlet systems of a combustion engine to one another in order to transfer exhaust gases from the outlet system to the inlet system. This line is usually valve-controlled in order to be able to modify according to the operating state of the engine the quantity of exhaust gases fed back to the inlet side of the engine. Exhaust gas feedback, also known as EGR (exhaust gas recirculation), is desirable during certain operating states in order to be able to hold down the engine's combustion temperature and thereby reduce the quantity of emissions from the engine.
Known technology has hitherto been unable, however, to indicate an effective method and device for appreciably reducing exhaust emissions during cold starting of combustion engines, particularly in the case of diesel-type combustion engines.